If you're up for a different type of challenge, you may want to consider using the cammo decals from Shinsengumi, which are designed for use on figures. I haven't used them yet, but the examples shown on their web site look pretty good.
Here is a link to the ACU pattern at HLJ. I just bought a couple of sets (BDU and DCU) from HLJ and will hopefully get them soon.
I know Pete Becerra had a really good-looking ACU figure on one of his Strykers a while back. He describes the technique he used (and the paints) in
this thread . Unfortunately the images are no longer visible.
Here is another discussion of the subject on a different forum.